1. Field of the Invention
The invention relates to an image forming apparatus and a control method for the image forming apparatus. More particularly, the invention relates to an image forming apparatus such as an electrophotographic printer or the like which can detect a status change in the apparatus such as presence or absence or jam of recording papers, another abnormality, or the like and to a control method for the image forming apparatus.
2. Related Background Art
Hitherto, in the image forming apparatus such as an electrophotographic printer or the like, various signals are transmitted and received between an image controller and a printer controller and the printer controller controls various mechanical parts in the printer on the basis of results of the signal reception, thereby performing a desired image forming process.
When a status change such as absence or jam of the recording papers, another abnormality, or the like occurs in the apparatus, the image controller is notified of information indicative of such a status change via the printer controller, thereby enabling the image controller to always confirm the presence or absence of the status change.
FIG. 8 is a timing chart showing generation timings of the various signals of the image forming apparatus.
That is, as shown in FIG. 8, when the printer controller detects a status change (absence of papers, or the like) of the printer engine at time t1, the printer controller changes a status change signal (CCRT signal) indicative of the status change from xe2x80x9cfalsexe2x80x9d to xe2x80x9ctruexe2x80x9d and transmits the xe2x80x9ctruexe2x80x9d CCRT signal to the image controller. The image controller which received the xe2x80x9ctruexe2x80x9d CCRT signal transmits a CBSY signal (strobe signal) as a serial command transmission permission signal to the printer controller and, thereafter, transmits a status request command (SR) to the printer controller by a serial command signal (CMD signal). Subsequently, the printer controller starts a preparation to return a status signal (STATUS) showing which status has been changed to the image controller. At time t2 when the preparation for returning is finished, the printer controller sets a status transmission permission signal, namely, SBSY signal (strobe signal) indicating that the preparation for returning the status information has been finished to xe2x80x9ctruexe2x80x9d and returns the xe2x80x9ctruexe2x80x9d SBSY signal to the image controller. At the same time, the printer controller resets the CCRT signal to xe2x80x9cfalsexe2x80x9d and, thereafter, transmits the status information to the image controller by the status signal (STS signal).
Techniques similar to that mentioned above have been also disclosed in Japanese Patent Applications Nos. 8-295066 and 9-146413.
In the above conventional image forming apparatus, however, after the status changes occurred and the CCRT signal was changed from xe2x80x9cfalsexe2x80x9d to xe2x80x9ctruexe2x80x9d at time t1 as mentioned above, the CCRT signal is reset from xe2x80x9ctruexe2x80x9d to xe2x80x9cfalsexe2x80x9d at time t2 when the preparation for returning the status signal is finished. However, as shown at time t3 in FIG. 9, if another status change occurs almost simultaneously with the reset timing to xe2x80x9cfalsexe2x80x9d of the CCRT signal, although the CCRT signal is instantaneously set to xe2x80x9cfalsexe2x80x9d, the xe2x80x9cfalsexe2x80x9d period becomes almost xe2x80x9c0xe2x80x9d. That is, for example, in the case where the CCRT signal is set to xe2x80x9ctruexe2x80x9d because of the occurrence of the absence of the papers and, thereafter, when the preparation for returning the status information is completed and the CCRT signal is changed to xe2x80x9cfalsexe2x80x9d, if another status change, for example, an error occurred in an optical system almost simultaneously with the change of the CCRT signal to xe2x80x9cfalsexe2x80x9d, the CCRT signal is immediately set to xe2x80x9ctruexe2x80x9d again. Thus, the xe2x80x9cfalsexe2x80x9d period becomes almost xe2x80x9c0xe2x80x9d.
It is desirable that the image controller recognizes the contents of the CCRT signal indicative of the status change at a period as early as possible and as promptly as possible. For this purpose, in many cases, the image controller detects the CCRT signal by an interruption detection input or the like in a hardware manner.
However, in the case where the user intends to detect the CCRT signal in a hardware manner, since there is a case where the xe2x80x9cfalsexe2x80x9d period of the CCRT signal becomes almost xe2x80x9c0xe2x80x9d as mentioned above, there are such problems that a limitation on designing is large in a filter setting for removing noises or the like and the reliability of the apparatus is also low.
In case of grasping the status change by detecting the change of the CCRT signal from xe2x80x9cfalsexe2x80x9d to xe2x80x9ctruexe2x80x9d, there is such a fear that the status change cannot be grasped.
The invention is made in consideration of the above problems and it is an object of the invention to provide an image forming apparatus which can raise a degree of freedom on designing and further improve the reliability and provide a control method for such an image forming apparatus.
According a preferred aspect of the invention, the above object is accomplished by an image forming apparatus comprising: image control means for controlling a formation of image data; image forming means for forming the image data onto a recording paper and outputting; and image formation control means for transmitting and receiving a signal to/from the image control means and controlling the image forming means, wherein the image formation control means has status change notifying means for detecting status change information of the image forming means and notifying the image control means of the status change information, status information forming means for forming status information of the image forming means when the status change information is notified to the image control means by the status change notifying means, status information notifying means for notifying the image control means of the status information formed by the status information forming means, and cancelling means for cancelling the status change information detected by the status change notifying means in response to after completion of the formation of the status information by the status information forming means, and the image formation control means has cancel state maintaining means for maintaining a cancel state cancelled by the cancelling means at least for a predetermined time.
According to another aspect of the invention, there is provided an image forming apparatus comprising: image forming means for forming an image onto a recording medium on the basis of image data sent from an external apparatus; obtaining means for obtaining status change information of the image forming means; status change notifying means for notifying the external apparatus of the status change information; status information forming means for forming status information of the image forming means when the status change information is notified; and cancelling means for cancelling the status change information after completion of the formation of the status information, wherein a cancel state cancelled by the cancelling means is maintained at least for a predetermined time.
According to still another aspect of the invention, there is provided a control method for an image forming apparatus, comprising: a status change notifying step of transmitting and receiving a signal between image control means for controlling a formation of image data and image formation control means for controlling image forming means for performing a forming process of the image data onto a recording paper and allowing the image formation control means to detect status change information of the image forming means and notify the image control means of the status change information; a status information forming step of forming status information of the image forming means when the status change information is notified to the image control means by the status change notifying step; a status information notifying step of notifying the image control means of the status information formed by the status information forming step; and a cancelling step of cancelling the detected status change information in response to completion of the formation of the status information by the status information forming step, wherein the method further comprises a cancel state maintaining step of maintaining the cancel state cancelled by the cancelling step at least for a predetermined time.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.